async函数仅在async函数中有效

Question

我正在尝试让计算聚合，以等待在fetch记录中解析的承诺。但我不能让等待起作用。这看起来是可以做的。但我不能让它在等待状态下工作。

我也试着把它包装在一个承诺中。但没有变化。

我收到错误:等待仅在异步函数中有效

const computeAggregate = async (model, sym) => {
    model.collection.distinct("minutes_offs", {
        symbol: sym
    }, function (error, distMinutes) {
        for (minuteIndex in distMinutes) {
            console.log("inside minutes off", distMinutes[minuteIndex]);
            try {

                const records = await fetchRecords(model, sym, distMinutes[minuteIndex]); //this does not work.
                const aggData = getAggregateData(records);
                createCollection(aggData);
            } catch (e) {
                console.log("error in computeAggregate", e);
            }
        }
    });
}

const fetchRecords = async (model, sym, minutesOff) => {
    console.log("compute function : input param", sym, minutesOff);
    var query = model.find({
        symbol: sym,
        minutes_offs: minutesOff
    }).sort({
        minutes_offs: +1
    });
    return query.exec();
};

Answer 1

您错误地使用了async / await：

const computeAggregate = (model, sym) => {
    model.collection.distinct("minutes_offs", {
        symbol: sym
    }, async (error, distMinutes) => {  // async is required here
        for (minuteIndex in distMinutes) {
            console.log("inside minutes off", distMinutes[minuteIndex]);
            try {

                const records = await fetchRecords(model, sym, distMinutes[minuteIndex]); //this does not work.
                const aggData = getAggregateData(records);
                createCollection(aggData);
            } catch (e) {
                console.log("error in computeAggregate", e);
            }
        }
    });
}

// async is not required here because you never use await
const fetchRecords = (model, sym, minutesOff) => {
    console.log("compute function : input param", sym, minutesOff);
    var query = model.find({
        symbol: sym,
        minutes_offs: minutesOff
    }).sort({
        minutes_offs: +1
    });
    return query.exec(); // this query.exec() must return a promise
};